Lessons in Spatial Analysis

Lauren Rosenshein Bennett gives a crash course in six techniques for spatial analysis.

Jul 23rd, 2012

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00:01So we're going to hear more from them later.

00:02But what all the students at Washington Lee share is a passion for solving spatial problems.

00:08Their class is about problem-based learning.

00:11So what we want to do is continue with that thought and provide a little more information...

00:15...about how we do spatial problem analysis and solve those kinds of problems.

00:20To do that, please welcome Lauren Rosenshein Bennett.

00:28Thanks, John. Instead of showing you one or two new tools and a specific application of those tools...

00:35...we're going to try something a little bit different this year, a kind of crash course in spatial analysis.

00:42We'll go through six techniques, from fundamentals like overlays to more advanced methods like interpolation.

00:49That way, you'll be ready to approach every problem with the best spatial analysis that ArcGIS 10.1 has to offer.

00:57The first technique is visual analysis, using geography to integrate multiple layers and gain new insight.

01:04In this example, we're looking at mortality rates 30 days after heart failure for Medicare beneficiaries.

01:14Now, ideally, we would expect the level of service provided to be consistent across the country...

01:20...but as we can see, there are areas of the country where those mortality rates are higher.

01:26So what could be going on here? Maybe it has something to do with hospital access.

01:32We can search for hospitals, add them to the map, and very quickly...

01:37...we can start to use a visual analysis to explore patterns and explore our data, all from ArcGIS Online.

01:46Now let's switch gears to technique number two, which is about overlays...

01:51...overlays that help us quantify the intersection of multiple datasets.

01:56In this example, we want to know the acreage of each type of land cover...

02:00...in Davy Crockett National Forest just south of Dallas, Texas.

02:05Prior to 10.1, to do this, we would've started by running an intersect, then follow that with a summary statistics...

02:14...and finally, we'd be able to compute - to create a Pivot table.

02:20We've combined this very common workflow into one simple tool called Tabulate Intersection.

02:28Now we have the acreage and the percentage of each type of land cover in the national forest...

02:34...all using an overlay that helps us compute the overlapping polygons and the intersection of those overlapping polygons.

02:43Technique number three is all about interpolating surfaces from discrete point data.

02:48In this example, we have data from USGS on lead concentrations in the state of Texas.

02:55So how do we create an accurate, continuous surface from this kind of sample data?

03:02In 10.1, a new tool, called empirical Bayesian kriging, does this for us with the simplicity of our most basic interpolation tools...

03:10...and the sophistication of our most advanced geostatistical methods.

03:16This analysis looks really simple, and it is really simple to run, but this is a lot more than just an interpolated surface.

03:25Because we're using a statistical approach to interpolation, we can look at not only the prediction surface...

03:31...but also the prediction error, giving us an understanding of the uncertainty in our predictions.

03:38These darker areas have a higher prediction error...

03:41...which is an indication that we may need to take additional samples in those locations.

03:47Which takes us to technique three and a half, which is all about spatial analysis everywhere.

03:53So let's grab our iPad and head out to the field just north of Austin.

03:58We'll start by collecting some samples.

04:00We'll add some data based on our latest soil samples, and when we're done, click this button.

04:11Sends that feature service to a geoprocessing service, which is running that advanced statistical interpolation, all from our iPad.

04:19It'll then return to us the latest surface based on that live data we're collecting out in the field.

04:31It really will.

04:43Okay. Not only do we get the latest surface based on the data we've collected out in the field...

04:52...we can also incorporate additional geoprocessing services.

04:56Oh, there we go. We can see pretty quickly how different that surface is based on that live data.

05:02And then we can run another service which is associated with this application, which is a watershed service.

05:09And what that will do is find the watershed that we're in as well as the average lead concentration in our watershed...

05:15...as well as the state of Texas and the rest of the United States.

05:19So by integrating these services throughout the platform, across devices, we're enabling everybody to do spatial analysis.

05:29Technique number four is network analysis, which is a type of analysis that many of you are doing every day.

05:36This technique is a little bit different because it's actually a sneak peek...

05:40...at the new ArcGIS Online world routing service being released this fall.

05:46We have a set of stops that we need to make this afternoon in the DC metro area...

05:50...and we want to route between them so that we can ensure we save time and money.

05:55So we'll use the Find Route tool, which we've hooked up to the new world routing service.

06:00The service combines advanced network analysis with worldwide optimized data, including live and historic traffic data.

06:11Now we can choose the time of day that we want to do the route, choose to optimize...

06:16...and send that analysis up to ArcGIS Online, up to that world routing service where it'll just do all the work for us.

06:23And like I said, this is a global service.

06:27With historic traffic data in 97 countries and live traffic data in 26 countries...

06:35...routing throughout Europe using live and historic traffic data is as simple as just a few clicks.

06:43Technique number five is about site selection, using demographics and market potential variables...

06:49...to choose the best location for a new store, for a targeted marketing campaign, or for a new public facility.

06:58In this example, we have a store that's performing really well in the Denver area...

07:03...and we have nine potential locations to put our next store.

07:07So how do we decide which is the best location?

07:11Well, we already know what success looks like, and we know the characteristics of our successful store.

07:17The powerful predictive tool in Business Analyst uses a principal components analysis...

07:22...to compare each of those potential locations to our successful store.

07:28We can choose from thousands of available variables, or we can choose an existing list, like the Retail Market Potential list...

07:37...which has close to 300 variables on consumer spending, census demographics, and more.

07:43The tool then uses a principal components analysis to assess the statistical similarity of each of those potential locations...

07:50...to our successful store and returns those ringed trade areas.

07:54So we can see the ones that are most similar to our successful store in darkest green.

08:00Taking the guesswork out of this kind of site selection can help us make more informed decisions.

08:07Technique number six is about finding clusters in our data.

08:12This takes us back to the Medicare data that we looked at earlier in ArcGIS Online.

08:17Now, we already saw that there's regional variation in these mortality rates, but we also know...

08:22...that assessing the quality and the cost of the Medicare system involves a lot more than just one variable.

08:28So we have data on readmission rates and standardized costs. So how do we make sense of all this data?

08:37A new tool in 10.1, called Grouping Analysis, lets us take these variables, bring them all together...

08:43...and create groups based on these variables that have similar characteristics.

08:50The first thing that we see is actually a spatial pattern based on those variables.

08:56But this report, which is also created by the Grouping Analysis tool, lets us dig in a little bit deeper.

09:01We can see that the red area in the Southeast is average in terms of mortality and readmissions...

09:07...but significantly higher in terms of spending than the rest of the country.

09:12So average level of service, much higher spending.

09:17This is an area we might want to focus our attention if our goal is cutting costs.

09:23The last thing that I want to show you is how easy it is for us to share our analysis using the new geoprocessing package.

09:30And this applies to techniques one through six and thousands more.

09:35Now, sharing our analysis is as simple as right-clicking on a result...

09:40...whether it's the simple run of a single tool or a complex model, and choosing to share it as a geoprocessing package.

09:47When we hit Share, it's taking our input data; our tools, which could include models with nested models and scripts...

09:55...any associated content; and our results, putting them all into one geoprocessing package...

10:01...and, in this case, sending them up to ArcGIS Online.

10:07Now we can take a look at our ArcGIS Online account and see that that geoprocessing package has been added.

10:14And this is a lot more than just the results of our analysis.

10:17This is our methodology, this is the tradecraft associated with that analysis.

10:22So we can share this with relevant groups and really contribute to the conversation in a meaningful way.

10:28These are just six of the thousands of ways that we can use spatial analysis to solve problems...

10:34...to make more informed, data-driven decisions.

10:38And you'll see all morning the way that spatial analysis plays a critical role in almost every workflow...

10:45...from the simple to the complex, from 3D to imagery, and everything in between. Thanks, John.

10:59Thanks, Lauren. One of the things that you might not have noticed is we're not talking about Desktop and Server...

11:05...and Mobile and Online, but instead, we're talking about one complete system.

11:10And spatial analysis, like everything else, cuts across the entire platform. All the boundaries are starting to blur together.

Copyright 2014 Esri
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